Present systems include a set of reed swtiches connected in parallel which generates an incorrect signal together with a set of reed switches connected in series which generates a correct signal to burglar-proof an alarm. With this arrangement, an alarm system can be disarmed and a door lock can be opened by turning on the set generating the correct signal, but input from the incorrect set will cause circuit to lock out. Though such a combination of reed switches can burglar-proof an alarm to some extent, the door lock can still be opened without tripping the alarm if a thief uses a third set of magnets. Because of this defect, the present invention has been designed to facilitate the activation of an alarm system and to provide lock-out protection.